1. Field of the Invention
The present invention relates to an exposure method and exposure apparatus for transferring a mask pattern onto a photosensitive substrate in an exposure body section. In particular, the present invention relates to the control of an exposure method and exposure apparatus when an error occurs in an air-conditioning system or temperature control system.
2. Description of Related Art
Exposure apparatuses used in a photolithography step in the manufacture of electronic devices such as semiconductor devices (e.g., integrated circuits) and liquid crystal displays are installed inside a clean room. However, because a purified environment is necessary, the exposure body section (which includes the apparatus body and the like described below), in particular, is installed inside a chamber such as an environmental chamber. An air-conditioning system is provided in the chamber, so that temperature control is performed inside the chamber. In addition, the air-conditioning system enables the air in the chamber to be purified by the use of filters such as high efficiency particle air (HEPA) filters and chemical filters and the like.
In many cases, at least a portion of a control system (i.e., a control unit) that performs the control of each section of the exposure body section that carries out exposure processing (i.e., performs movement control of movable sections such as a stage, controls exposure conditions, controls transporting systems such as those for the mask and photosensitive substrate (i.e., substrates such as wafers and glass plates on whose surface photoresist has been coated—referred to below simply as “wafers”), and performs other control) and also supplies power and the like is mounted integrally inside a chamber that houses the apparatus main body, or is located close to the apparatus main body. In addition, a temperature control system that cools instruments that heat up comparatively easily such as motors for the optical system and transporting systems is provided in the apparatus main body.
If an error occurs in such air-conditioning systems and temperature control systems, the error is made known to an operator or the like, however, if there is a delay in the recovery operation by the operator, then the temperature of the apparatus main body and inside the chamber may increase considerably due to the heat generated by the aforementioned control system. In this case, there is a possibility that the recovery in the apparatus main body will be hindered by harmful effects caused by the heat generated by the control system, such as the placement condition of optical elements being changed, or the optical characteristics of the optical elements themselves being changed because of a difference between the coefficient of thermal expansion of the optical elements and the coefficient of thermal expansion of holding members that hold the optical elements. Moreover, even if no error occurs in the air-conditioning system or temperature control system, if the respective power supplies of the air-conditioning system, the temperature control system, and the control system are not shut down in the correct sequence, then there is the possibility that, in the same way as is described above, heat generated by the control system and the like will have a deleterious effect on the performance of the apparatus (i.e., on the characteristics of the optical system and the like). Exposure apparatuses that purge at least a portion of an optical path of exposure illumination light inside the chamber using an inert gas such as nitrogen or helium are currently in practical use, however, in these exposure apparatuses there is the possibility that, if the power supplies of gas supply apparatuses that supply inert gases and the like are shut down without consideration given to the timing of the shutting down of the control system and the like, the same problems as those in the above described air-conditioning systems and temperature control systems will be created.